docs: def validate_value(self, value):
          """Validate new user/group value against any User/Group restrictions
  
          Attempts to resolve generic UserGroup instances if necessary to respect special "Everyone" group, and
          "All Users" + "All Groups" options
          """
          super(UserGroupField, self).validate_value(value)
  
          if value is not None:
              # Ignore validation if all users + groups are allowed
              if self._show_all_groups and self._show_all_users:
                  return
  
              # Try to directly check allowed ids against user/group id first to avoid having to resolve generic
              # UserGroup with an additional request
              if value.id in self._allowed_user_ids | self._allowed_group_ids:
                  return
  
              # Resolve to check Users vs Groups separately
              value = value.resolve()
  
              if isinstance(value, User):
                  self._validate_user(value)
              else:
                  self._validate_group(value)